AbstrAct: Strategic uncertainty is the disparity between what one knows, and what one needs to know in order to make a responsible decision; it permeates defense decision-making. Because of strategic uncertainty, planners must maximize the robustness against surprise in striving to achieve critical goals. This article describes the decision methodology known as robust-satisfying and the integration of this method with other military decision-making processes.

F lipping a fair coin has equal chance of getting heads or tails. Rolling a balanced dice has equal probabilities for each of six known outcomes. But if we take this into the realm of strategic decision-making and consider the 2002 assessment of Iraqi capability with Weapons of Mass Destruction (WMD), how many outcomes should we ponder: what are they and what are their likelihoods? One might say the answer is binary: Either they do or they do not have WMD. Or, perhaps we should consider multiple possibilities: They have small (or large) quantities, they are (or are not) developing more, and they intend to use it (or not). It is as though we are rolling dice without knowing how many faces each die has, and whether or not each is balanced for equal probabilities of all outcomes. This is essentially the problem every strategist faces, and the one this article proposes to address.

We often are justified in thinking probabilistically and in saying something is very likely. For example, Stalins military advisers in 1941 claimed a German invasion of the Soviet Union was very likely. The advisers had reconnaissance evidence, captured documents, and more.1 Most analysts (though not Stalin) readily acknowledged the comple-mentary assertion Germany is not about to invade Russia was very unlikely.

In binary logic, an assertion is either true or false. If we know an assertion is true, then we know the negation of that assertion is false. There is an excluded middle in binary logic. The excluded middle rules out the possibility an assertion is both true and false. Probabilistic thinking is an extension to the domain of uncertainty of the binary thinking of pure logic: If we know an assertion is highly probable, then we know the negation of that assertion is highly unlikely. An assertion and its negation cannot both be highly likely when using probabilistic reasoning.

Yakov Ben-Haim is a professor of mechanical engineering and holds the Yitzhak Modai Chair in Technology and Economics at the TechnionIsrael Institute of Technology. He initi-ated info-gap decision theory for modeling and managing severe uncertainty. Info-gap theory is applied around the world in engineering, biological conservation, economics, project management, natural hazard response, national security, medicine, and other areas.

64 Parameters 45(3) Autumn 2015

In strategic affairs, we often do not know enough about the situation to exclude the middle as we routinely do in binary logic and in probabi-listic thinking. The British during World War II could have viewed the assertion that Germany was trying to build an atomic bomb as quite likely (indeed they were). Otto Hahn, who was a war-time professor in Berlin, had visited Enrico Fermi during the latters experiments with uranium in the 1930s, and Hahn won the 1944 Nobel Prize in Chemistry (awarded in 1945) for his discovery of fission of heavy nuclei.2 But one could argue the Nazis abjured Jewish physics, such as relativity and quantum theory, and therefore it is quite unlikely Germany would try to exploit this physics in order to build an atom bomb. Indeed, the Nazis never pursued nuclear weapons as enthusiastically as the Allies.

If one needs to say an assertion is both quite likely and quite unlikely, one must abandon the binary structure of probability. This need arises quite often in strategic affairs. One reason is conflicting intelligence reports are common, as the Prussian military thinker Carl von Clausewitz emphasized.3 Another reason is we often are unaware of, or do not understand, new doctrinal or technological possibilities. For instance, the possibility and implications of massive infantry use of hand-held Sagger anti-tank ordnance surprised the Israelis in the Yom Kippur War, despite their experiences with similar missiles both as users and as targets.4 Furthermore, prediction is always difficult, espe-cially in war. For example, P.M.H. Bell discusses the unpredictability of Stalingrad as a turning point in the war, whose outcome was uncertain even in 1944.5

The uncertainty confronting the strategic planner is often less struc-tured and less well characterized than probabilistic uncertainty. We will define strategic uncertainty as the disparity between what we do know and what we need to know in order to make a responsible decision. Strategic uncertainty is a functionally important information-gap, and it has two elements. First, the domain of possibilities is unbounded and poorly characterized. This is different from probabilistic uncertainty where we know the domain of possible outcomes (even though this domain may be huge and complex). The second element of strategic uncertainty is that it is functionally important because it impacts the outcome of a decision. We are explicitly concerned with outcomes, and with uncertainties that may jeopardize critical goals or may be exploited to achieve desired outcomes.

Doing Our Best: Optimization is Not What it SeemsManaging strategic uncertainty is difficult. The successful response

to strategic uncertainty is to acknowledge it and to struggle with it, but to recognize that strategic uncertainty is ineradicable.

The pervasiveness of uncertainty has profound implications for what it means to do ones best in many areas, including military

5 P.M.H. Bell, Twelve Turning Points of the Second World War (New Haven: Yale University Press, 2011), 95, 231.

Thinking STraTegically Ben-Haim 65

strategy. The decision methodology, which could be called outcome-optimization, begins by identifying the best available information, understanding, and insight, including perhaps assessments of uncer-tainty. We will call this information our knowledge. This knowledge entails information and understanding about friendly and adversarial capabilities, geopolitical constraints and opportunities, terrain, logistics, etc. Outcome-optimization chooses the option whose knowledge-based predicted outcome is best.

Outcome-optimization is usually unsatisfactory for decision-making when facing strategic uncertainty because our knowledge is likely wrong in important respects. Instead, we will advocate the decision methodol-ogy of robustly satisfying outcome requirements.6 The basic idea is to identify outcomes that are essential goals that must be achieved and then to choose the decision that will achieve those critical outcomes over the greatest range of future surprises.

We use our knowledge in two ways. First, to assess the putative desirability of the alternative decisions, and second, to evaluate the vul-nerability of those alternatives to surprising future developments. The robust-satisfying strategy is the one with maximal power against stra-tegic uncertainty while satisfying critical requirements. In other words, the outcome will be satisfactory, though not necessarily optimal, over the greatest range of future deviations from our current understanding. Of course, what constitutes a satisfactory outcome can be as modest or as ambitious as one wants.

A simple preliminary example is the robust satisfying response to a surprise attack. The immediate critical goals are to protect and sta-bilize the attacked force and to assess the strength and deployment of the attacking force. Actions are taken that depend minimally on the limited and uncertain knowledge about the attacker. Uncertainty about the attacker will usually preclude an immediate attempt to achieve an optimal outcome such as annihilating the attacker. Subsequently, the critical goals change and the response evolves accordingly.

Colin Gray expressed something very close to the idea of robust satisfying when he wrote:

You cannot know today what choices in defense planning you should make that will be judged correct in ten or 20 years time. Why? Because one cannot know what is unknowable. Rather than accept a challenge that is impossible to meet, however, pick one that can be met well enough. Specifically, develop policy-makers, defense planners, and military executives so that they are intellectually equipped to find good enough solutions to the problems that emerge or even erupt unpredictably years from now. The gold standard for good enough defense planning is to get the biggest decisions correct enough so that ones successors will lament if only ... solely with regard to past errors that are distinctly survivable.7

The goal of the methodology we are calling robust-satisfying is to achieve specified critical objectives reliably. This is different from attempting

6 Further discussion of ideas in this section are found in Yakov Ben-Haim, Strategy Selection: An Info-Gap Metho